Back spacing mechanism



July 27, 1937. J. F. KocA BACK SPACING MECHANISM Filed March 2, 1933 4 Sheets-Sheet 1 July 27, 1937. J. F. KocA BACK SPACING MECHANISM Filed March 2',

1933 4 Sheets-Shea?l 2 July 27, 1937. J. F. KocA 2,088,064

BACK SPAC ING MECHANISM Filed March 2, 1933 4 Sheets-Sheet 5 July 27, 1937. J. F. KocA BACK'SPACING MECHANISM Filed March 2, 1933 4 Shee'bs-Shee'll 4 Patented July 27, 1937 UNITED STATES PATENT OFFICE BACK SPCING MECHANISM Application March 2, 193s, serial Nofssasss 19 Claims.

This invention relates to typewriters and particularly to shift mechanism for typewriters. More specifically the invention relates to mechancally operated electrically controlled back"spac ing mechanism for electrically operated typewriters.

The primary object of the invention is to provide new and improved back spacing mechanism for electrically operating an escapement rack and consequently the carriage upon the depression of a single key lever.

Another object is to provide new and improved means for back spacing the carriage one notch upon the depression of a single key lever.

A further object is to provide new and improved means for back spacing the carriage continuously and intermittently one notch at a time when a single key lever is continuously depressed.

A still further object is to provide novel and improved means for preventing operation of the back spacing mechanism when the carriage has reached the end of its back space movement.

Still another object is to provide new and improved-means operated by a driven auxiliary shaft for selectively back spacing the escapement rack and consequently the carriage one space upon the depression of a key lever, or continuously but intermittently upon depression of another key lever and providing means cooperating with said mechanism for preventing operation of the back spacing mechanism when the carriage has reached the end of its back spaced position.

Numerous other objects and advantages will be apparent throughout the progress of the following specification.

The accompanying drawings illustrate a selected embodiment of the invention and the views therein are as follows:

Fig. 1 is a transverse detail sectional view ithrough a typewriter and embodying the invenion.

Fig. 2 is a detail rear elevation, parts being broken away for the sake of clearness.

Fig. 3 is a detail plan section showing some of the operating mechanism.

Fig. 4 is a detail transverse sectional view showing some of the parts shown in Fig. 3 and Fig. 1.

Fig. 5 is a detail sectional view showing several of the parts in Fig. 1 with the parts in partly advanced position.

Fig. 6 is a detail rear elevation partly in section. A

The typewriter to which the invention refers has a frame I8 which supports the front and rear carriage rails II and I2 respectively supporting a carriage I3. The particular typewriter herein shown for the purpose of illustration is a Woodstock typewriter and, in general, includes certain parts which are standard on Woodstock machines. Various parts will not be described except those in conjunction with the various members for mechanically shifting the carriage. A drive shaft I4 is electrically driven by a belt cooperating with a pulley I5 xed to an auxiliary shaft I6. A main drive pulley I1 is also fixed to the auxiliary shaft I6 and is driven by a motor, not shown. The drive shaft I4 is for the purpose of mechanically driving the type bars in a manner well known in the art.

A back space key lever I8 is pivotally supported at I9 to a. sub-frame 2D, there being a. spring 2| to urge the key lever I8 in its normal initial upward position.

A link 22 is pivotally connected to the key lever I8 as indicated at 23 and is operatively connected to a. lever 24 as indicated at 25, Fig. 1. The lever 24 is pivoted to a shaft 26 and has an arm 21 which carries a pawl 28 which is pivoted to the arm 21 as indicated at 29. 'I'he pawl 28 has a latching end 30 which is adapted to latch with a latching end 3| on a latch 32. The latch 32 is pivoted at 33 to an ear 34 which is struck out from an end bracket 35. A spring 36 is connected to the latch 32 and urges the latch 32 in a downward, direction, being limited by a tailpiece 31 which is adapted for, engagement with the bracket 35 as indicated at 38. The latch 32 has a locking pawl 39 which is adapted to engage a pawl 40 pivoted at 4I to a cam 42. 'I'he cam 42 is revolubly mounted on the auxiliary shaft I6. The pawl 48 is provided with a locking end 43 which is adapted to engage a tooth 44 on a driving ratchet 45 which is fixed to the shaft I6 and rotates therewith. Therefore, upon depression of the back space key lever I8, the link 22 will swing the arm 24 on its pivot26, raise the pawl 28 which in turn will lift the pawl 39 out of engagement with the pawl 46. As soon as the pawl 39 is disengaged from the pawl 40, a spring 46 connected to the tail-piece 41 of the pawl 40 will cause the locking end 43 to become engaged with a tooth 44 on the ratchet 45. This engagement will cause the cam 42 to become locked to the shaft I6 and rotate therewith. The pawl 28 is provided with a tail-piece 48 which will be engaged by the pawl 40 during rotation of the cam. This engagement will move the pawl 28 to the left, Fig. 1, and allow the latch 32 to return to its original normal position where it will again be in the path of the pawl to disengage the locking end 43 from the ratchet 45 at which time the cam will cease operating.

During rotation of the cam 42, a cam follower or roller 49, which rides on the peripheral surface of the cam 42, will operate a crank 50, the crank having the cam follower or roller 49 pivoted thereto. When the roller 49 is on the rise 5| of the cam 42, the crank 50 will be swung on its pivot 52 and raise its rear end 53. A link 54 is pivoted to the rear end 53 of the crank as indicated at 55. The upper end 56 of the link 54 is bent at right angles as indicated at 51 to provide an attaching ear 58. A crank 59 pivoted at 60 to a part of the main frame i0 has a pivotal connection 6l with the ear 58 of the link 54. The arm 62 of the crank 59 has a pawl 63 pivoted thereto as indicated at 64. A spring 65, connected to the tail-piece 56 of the pawl 63 and to an ear 61 on the crank 59, normally urges the face 68 of the tail-piece toward a stop ear 69. The pawl 63 is normally held out of engagement with the stop ear 69 and the teeth 10 of the escapement rack 1| by the end 12 of a slot 13 formed in a supporting plate 14, Fig. 6. However, during operation of the cam, the link 54 will be pushed upwardly, swing the crank 59 on its pivot 60 and move the pawl 63 toward the teeth 10 on the escapement rack 1|. However, as the cam follower advances toward the rise of the cam. the crank 59 will be given additional swinging movement causing the stop ear 69 to engage the face 68 of the pawl 63 and positively position the tooth 15 of the pawl 63 into the space between a pair of teeth 10 and move the escapement rack toward the left one space, Fig. 6. As soon as the escapement rack 1| has been moved one space by the pawl 63, the face 16 of the pawl 63 will be in contact with the face 11 of the slot 13. The engagement of the face 16 with the face 11 will lock the pawl in the teeth and prevent overthrow. As soon as the pawl 63 has moved the escapement rack one notch, the cam will have made one complete revolution and the pawl 40 will again have engaged the pawl 39 at which time the cam roller will return to the low spot of the cam, returning the parts to their normal initial position as shown in Fig. 1. The pawl 28 has a spring 18 fastened thereto to urge the pawl in a predetermined position. The movement of the pawl is limited by an ear 19 which is in engagement with the arm 21 of the' lever 24. A spring 80, Fig. 6, is fastened to the crank 59 and assists in returning the parts. Therefore, upon the single depression of the back space key lever |8, the escapement rack will only be advanced one notch, consecutive operation of the pawl 63 being prevented by the return of the pawl 39 into thepath of the pawl 40 and stopping further rotation of the cam with the shaft.

Where the back spacing operation is to be repeated, a repeat lever 8|, Fig. 3, is provided. This repeat lever 8| is provided with a link 82, Fig. 4, pivoted at 83 to a lever 84. The lever 84 is pivoted on the shaft 26, Fig. 4, and carries a pawl 85 which is pivoted at 86 to its arm 81. The pawl 85 has a latching end 88 which is adapted for engagement with the latching end 3| of the latch 32. The pawl 85 is provided with an ear 89 which engages the arm.81 to limit the pivotal movement of the pawl 85. A spring 90 is fastened to the arm 81 and to the pawl to urge the pawl 85 in a predetermined direction normally into engagement with the latching end 3| of the latch 32. When the repeat lever 8i is depressed, the link 82 will swing the lever 815 on its pivot 26, raise the latch 32 and cause disengagement of the pawl 39 from the pawl 40 and the cam and other parts controlled thereby will operate in the manner previously described. Continued depression of the lever 8|, however, will cause continued operation of the parts to continuously and consecutively cause the pawl 96 to become engaged and disengaged from the escapement rack 1| and continuously and intermittently move the escapement rack one notch at a time. This continued operation is effected because the pawl 85 does not carry a tail-piece 48 to becomeengaged by the pawl 40 to return the parts to normal position. Continued depression of the repeat lever 8| keeps the latching end 39 of theI latch 32 from becoming engaged with the pawl 40. Therefore, the cam will continue to rotate until the depression of the repeat lever is released.

However, if the repeat lever were depressed until the carriage reaches the end of its back spaced movement, the parts would become damaged and broken as the carriage has reached the end of its travel. Therefore, means are provided to automatically return the latch 32 into the path of the pawl 40 to prevent continued rotation of the cam irrespective of the position of the repeat lever 8|. These means comprise margin stop mechanism 9| including an arm 92 pivoted to the main frame I0 as indicated at 93. The margin stop mechanism 9| is conventional with Woodstock typewriters as shown and disclosed in the copending application, Serial No. 659,332, filed concurrently herewith, and includes the slot and pin connection 94, Fig. 2, to permit slidable movement of the margin stop mechanism in the usual manner. The margin stop mechanism 9| also includes the adjustable margin stop 95 and the xed limit stop 96 which is also shown and described in the aforesaid copending application. When either the face 91 of the marginal stop 95 or the stop 96 engages the face 98 of the marginal stop mechanism 9|, the arm 92 will be moved the limit of the pin and slot connection 94 as also described in the afore said copending application. When the arm 92 is moved by either the marginal stop 95 or the fixed stop 96, the link 99 pivoted to the arm 92 as indicated at |00, will move the bell-crank |0| to the left, Fig. 2. The bell-crank |0| is pivoted at |02 to the bracket 36 and has its upper end pivotally connected; at |03 to the link 99, Fig. 2. The bell-crank |0| has a lower arm. |04 formed integrally therewith which is adapted to engage an arm |05 of a bell-crank |06 which is pivoted at |01, Fig. 1, to the ear 34 of the bracket 35. The upper arm |08 of the bell-crank |06 has a formed-over portion |09. Fig. 2, terminating in an ear ||0 to receive the 'rear ends of links Fig. 1, and ||2, Fig. 4. The links and ||2 have end slots H3, and a fastening member ||4 passes through the arm |08 of the bell-crank, the slots ||3 and the ear ||0. The links and ||2 are pivoted to the pawl 28 and the pawl 85 respectively by pivots I5 and ||6 respectively. The movement of the arm 92 moves the link 99 and bell-crank |0| which raises the arm |95 of the bell-crank |06. The movement of the bell-crank |06 moves the links and ||2 to the left, Figs. 1 and 4, and moves the pawls 28 and 85 out of engaging position with the latch 32. These pawls will have no effect on the latch 32 and the latch 32 will remain in the posiaosaqec tion shown in Figs. 1 and 4 in engagement with the pawl 40 preventing operation of the cam. Therefore, when the carriage has reached the end of its back space travel, the pawls 39 and 40 will remain in engagement. even though the back space lever or the repeat lever is depressed. The ends of the links and ||2 are provided with slots ||3 to prevent the pawl 28, when displaced by the tail-piece 48, from releasing the pawl 85 because the engagement of the pawl 40 with the tail-piece 48 will merely slide the link the length of its slot 3 and prevent disengagement of the latching end 3| of the latch 32 with the latching ends 30 and 88 of the pawls 28 and 85 respectively.

A detent ||1 is urged upwardly by a spring ||8 and has a recess/H9 which is adapted to receive a pin on the cam 42 as shown in Figs. 1 and 5 to assist in holding the cam in its normal initial or rest position.

Operation,

When the back space lever I8 is depressed, the link 22 will swing the arm 24, and raise the pawl 28 which will in turn raise the latch'36 and free the pawl 40 from the pawl 39. The spring 46 will, therefore, pull the latching end 43 of the pawl 40 into engagement with the ratchet and the cam 42 will rotate. The rotation of the cam 42 will move the crank 58 and cause the link 54 to be pushed upwardly and swing the crank 49 on its pivot lill to cause the pawl 63 to engage the teeth 10 on the escapement rack 1| and move the escapement rack one notch where the escapement rack 1| will be held in its back spaced position by the usual escapement mechanism. The spring 36, during the aforementioned operation, will pull the latch into position to be engaged by the pawl 40 to stop further rotation of the cam because the engagement of the pawl 40 with the pawl 39 on the latch 32 will release the latching end 43 of the pawl from the ratchet 45. As soon as the cam has completed its travel, the parts will be returned to their normal initial position.

When the repeat lever 8| is depressed, the link 82 will rock the arm 84 onits pivot and cause the pawl 85 to raise the latch 32 to disengage the pawl 39 from the pawl 40. The cam is then free to rotate continuously to continuously move the escapement rack one notch at a time intermittently. When, however, the carriage has reached the end of its back spaced movement, the marginal stop mechanism 9| will cause movement of the arm 92. Movement of the arm 92 will operate the bell-crank ||J| which, in turn, will operate bell-crank |05 to move the links and ||2. Movement of the links and ||2 will shift the pawls 28 and 85 out of operative engagement or into inoperative position relative to the latch 32. Therefore, the latch 32 will be pulled by the spring 36 into position and into locking engagement with the pawl 40 to prevent rotation of the cam with the shaft I6.

The invention provides new and improved back spacing mechanism for electrically operating an escapement rack by the depression of a single key lever, the operation of the escapement rack causing movement of the carriage. The back spacing mechanism is adapted to selectively back space one space at a time or back space the carriage successively and continuously. Parts of the mechanism for single back spacing arerprovided for causing the continuous back spacing operation, means being provided to kick-out or trip certain mechanism to prevent operation of the back spacing mechanism when the carriage has reached the end of its travel. The parts are rigidly constructed and are compactly arranged. The mechanism is relatively simple and is not likely to get out of order.

Changes may be made in the form, construction, and arrangement of the parts without departing from the spirit ofthe invention or sacricing any of its advantages, and the right is hereby reserved to make all such changes as fairly fall within the scope of the following claims.

The invention is hereby claimed as follows:

1. Back space mechanism for typewriters comprising a key lever, a carriage, an escapement rack on the carriage, an electrically driven shaft, and operating means cooperating with the driven shaft and controlled by the key lever for operating the escapement rack for back spacing the carriage, and means for preventing operation of said operating means when the carriage is in fully back spaced position.

2. Back space mechanism for typewriters comprising a. key lever, a carriage, an escapement rack on the carriage, operating means controlled by the key lever and cooperating with the escapement rack for back spacing the carriage successively as long as the key lever is depressed, and means for preventing operation of said means when the carriage has reached the extent of its travel.

3. Back space mechanism for typewriters comprising a,key lever, a carriage, an esoapement rack on the carriage, electrically operated means controlled by the key lever and cooperating with the escape-ment rack for back spacing the carriage one space upon depression of the key lever, a repeat back space lever, and means cooperating with the rst named means and controlled solely by the repeat lever for successively back spacing the carriage.

4. Back space mechanism for typewriters comprising a key lever, a carriage, an escapement rack on the carriage, operating means controlled by the key lever and cooperating with the escapement rack for back spacing the carriage one space upon depression of the key lever, a repeat back space lever, means cooperating with said operating means and controlled by the repeat lever for successively back spacing the carriage, and means for preventing operation of the operating means when the carriage has reached the extent of its back space travel.

5. Back space mechanism for typewriters comprising a pair of key levers, a carriage, an escapement rack carried by the carriage, means v engageable with the escapement rack for back spacing the carriage, mechanism including a rotary shaft for operating the last named means, and'means associated with both of said levers for causing operation of said mechanism to move the carriage upon depression of either of said levers, and means for preventing operation of said mechanism to move the carriage when the latter is in fully back spaced position.

6. Back space mechanism for typewriters comprising a pair of key levers, a carriage, an escapement rack carried by the carriage, vmeans engageable with the escapement rack for back spacing the carriage, mechanism for operating the last named means, means selectively associated with one of said levers for causing operation of said mechanism to move the carriage one space upon depression of the last named key lever, and

means selectively associated with the other key lever to back space the carriage successively and continuously upon continued depression of said other key.

7. Back space mechanism for typewriters comprising a pair of key levers, a carriage, an escapement rack carried by the carriage, means engageable with the escapement rack for back spacing the carriage, mechanism for operating the last named means, means associated with one of said levers for causing operation of said mecha.- nism to move the carriage one space upon depression of the last named key lever, means associated with the other key lever to back space the carriage successively and continuously during depression of said other key, and means for preventing operation of said mechanism when the carriage has been moved to the end of its back space travel.

8. Back space mechanism comprising a rotary shaft, a ratchet fixed to the shaft and rotatable therewith, a cam freely mounted on the shaft, a key lever, a carriage, an escapement rack carried by the carriage, means adapted for coopera.- tion with the rack and controlled by the rotation of the cam to back space the carriage, a key lever, and means controlled by the key lever when depressed to lock the cam to the ratchet for rotation with the shaft and thereby back space the carriage, and means for preventing rotation of the cam when the carriage has been back spaced the extent of its travel.

9. Back space mechanism comprising a rotary auxiliary cam shaft, a ratchet fixed to the shaft and rotatable therewith, a cam freely mounted on the shaft, a key lever, a carriage, an escapement rack carried by the caniage, means adapted for cooperation with the rack and controlled by the rotation of the cam to back space the carriage, a key lever, means controlled by the key lever when depressed to lock the cam to the ratchet for rotation with the shaft and thereby back space the carriage, trip means for releasing the cam from the ratchet when the carriage is back spaced one space, a second key lever, and means controlled by the depression of the second lever to lock the cam to the ratchet to back space the carriage repeatedly.

10. Back space mechanism comprising a rotary auxiliary cam shaft, a ratchet fixed to the shaft and rotatable therewith, a cam freely mounted on the shaft, a key lever, a carriage, an escapement rack carried by the carriage, means adapted for cooperation with the rack and controlled by the rotation of the cam to back space the carriage, a key lever, means controlled by the key lever when depressed to lock the cam to the ratchet for rotation with the shaft and thereby back space the carriage, trip means for releasing the cam from the ratchet when the carriage is back spaced. one space, a second key lever, means controlled by the depression of the second lever to lock the cam to the ratchet to back space the carriage, and means for preventing operation of the trip means during depression of the second lever.

11. Back space mechanism comprising a rotary auxiliary cam shaft, a ratchet fixed to the shaft and rotatable therewith, a cam freely mounted on the shaft, a key lever, a carriage, an escapement rack carried by the carriage, means adapted for cooperation with the rack and controlled by the rotation of the cam to back space the carriage, a key lever, means controlled by the key lever when depressed to' lock the cam to the ratchet for rotation with the shaft and thereby back space the carriage, trip means for releasing the cam from the ratchet when the carriage is back spaced one space, and means for preventing rotation of the cam when the carriage has been back spaced the extent of its travel.

12. In an electric typewriter having an electrically driven type bar driving shaft, the combination of an auxiliary shaft adapted to be driven simultaneously with said type shaft, a cam freely mounted on the auxiliary shaft, a carriage, an escapement rack carried by the carriage, a toothed pawl adapted for engagement with the rack to back space the carriage, means for locking the cam to the auxiliary shaft to rotate therewith, and means controlling the rotation of the cam to operate the pawl and move the carriage one space ata. time, said last named means including a trip member conditioned by movement of the cam for disabling the locking means after a predetermined amount of cam'rotation.

13. In an electric typewriter having an electrically driven type bar driving shaft, the combination of an auxiliary shaft adapted to be driven simultaneously with said type shaft, a cam freely mounted on the auxiliary shaft, a carriage, an escapement rack carried by the carriage, a toothed pawl adapted for engagement with the rack to back space the carriage, means for locking the cam to the auxiliary shaft to rotate therewith, means controlling the rotation of the cam to operate the pawl and move the carriage one space at a time, and additional means controlling the operation of the cam to cause successive intermittent back spacing of the carriage.

14. In an electric typewriter having an electrically driven type bar driving shaft, the combination of an auxiliary shaft adapted to be driven simultaneously with said type shaft, a cam freely mounted on the auxiliary shaft, a carriage, an escapement rack carried by the carriage, a toothed pawl adapted for engagement with the rack to back space the carriage, means for locking the cam to the auxiliary shaft to rotate therewith, means controlling the rotation of the cam to operate the pawl and move the carriage one space at a time, additional means controlling the operation of the cam to cause successive intermittent back spacing of the carriage, and devices for selectively causing operation of either of said two last named means.

15. In an electric typewriter having an electrically driven type bar driving shaft, the combination of an auxiliary shaft adapted to be driven simultaneously with said type shaft, a cam freely mounted on the auxiliary shaft, a carriage, an escapement rack carried by the carriage, a toothed pawl adapted for engagement with the rack to back space the carriage, means for locking the cam to the auxiliary shaft to rotate therewith, means controlling the rotation of the cam to operate the pawl and move the carriage one space at a time, additional means controlling the operation of the cam to cause successive intermittent back spacing of the carriage, devices for selectively causing operation of either of said two last named means, and means controlled by the position of the carriage to prevent operation of both of said two last named means upon operation of either or both of said devices.

16. In a back space mechanism for typewriters, a carriage, a continuously operable power driven shaft, means engageable with the carriage for back spacing it, a key lever, means operated by the key lever for connecting the power shaft and the back spacing means, means automatically operable after a single operation of the back spacing means for disconnecting said means from the power shaft, a second key lever, and means operated by the second key lever for connecting the power shaft and the back spacing means for continuous and successive operation of the latter, each of said key levers being selectively and independently operable to control its operating mechanism and eiect back spacing of the carriage.

17. Ina back space mechanism for typewriters, a carriage, a continuously operable power driven shaft, means engageable with the carriage for back spacing it, a key lever, means operated by the key lever for connecting the power shaft and the back spacing means, and means controlled by movement of the carriage fordisconnecting said connecting means when the carriage is in fully rack and controlled by the rotation of the cam to back space the carriage, a key lever, means controlled by the key lever when depressed to lock the cam to the ratchet for rotation with the shaft and thereby cause operation of the back spacing means, trip means conditioned by rotation ofthe cam for releasing the cam from the ratchet when the carriage is back spaced one space, and

means cooperating with the back spacing means 1 to prevent overthrow of the carriage.

19. In a back space mechanism for typewriters, a carriage, a continuously operable power driven shaft, means engageable with the carriage for back spacing it, a pair of key levers,` means operated by one of said key levers for connecting the power shaft and the back spacing means to cause said `means to back space the carriage one space, and means operated by the other of said key levers for connecting the power shaft to the back spacing means to cause said means to back space the carriage a plurality of spaces, each of said key levers being selectively and independently operable.

JAMES F. KOCA. 

